Means for maintaining the constancy of the working plane of grinding and/or polishing tools



May 22, 1956 E. LAVERDISSE 2,746,213

MEANS FOR MAINTAINING THE CONSTANCY OF THE WORKING PLANE OF GRINDING AND/OR POLISHING TOOLS Filed Nov. 12, 1953 5 Sheets-Sheet 1 May 22. 1956 E. LAVERDISSE 2,746,213

MEANS FOR MAINTAINING THE CONSTANCY OF THE WORKING PLANE OF GRINDING AND/OR POLISHING TOOLS Filed NOV. 12, 1953 3 Sheets-Sheet 2 .LLL\\\ uwuzmuumwumwuuu lll-lllllllll llllll Illlll III-[11mm May 22, 1956 E. LAVERDISSE 2,746,213

MEANS FOR MAINTAINING THE CONSTANCY OF THE WORKING PLANE OF GRINDING AND/OR POLISHING TOOLS Filed NOV. 12, 1955 3 Sheets-Sheet 3 United States Patent MEANS FOR MAINTAINING THE CONSTAN CY OF THE WORKING PLANE OF GRINDING AND/ OR POLISHING TOOLS Edmond Laverdisse, Chateau St. Roch, Auvelais, Belgium,

assignor to Les Glaceries de la Sambre, Societe Anonyme, Auvelais, Belgium, :1 Belgian company Application November 12, 1953, Serial No. 391,697

Claims priority, application Belgium November 20, 1952 7 Claims. (Cl. 51-112) The present invention relates to apparatus for the simultaneous grinding and/or polishing of the two faces of a sheet of glass, in which the sheet of glass, resting on conveyor members, usually rolls, passes between grinding or polishing tools which turn about axes perpendicular to the supporting plane of the sheet and are urged axially towards the respective faces of the latter.

The invention has for its object to obviate the bending moments which are capable of causing the fracture of the glass and to which the sheet is subjected when the working plane of the lower tools ceases to be in alignment with the supporting plane of the sheet on the conveyor members, as a result of the wear of the tools and/or of the axial displacement imparted to the said tools for compensating for the wear.

This object is achieved in accordance with the invention by providing stops adapted to limit the axial displacement of the tools towards one another in such manner as to stabilize the working plane of the lower tools in the supporting plane of the sheet of glass.

Stops are advantageously provided for the tools located at the two sides of the sheet of glass, but it may be sufiicient to provide them for the tools disposed at one side of the sheet only. Preferably, in both cases, the stops limiting the axial displacement of the tools situated on one side of the sheet of glass are disposed on the other side of the sheet and the tools bear on the stops by the intermediary of the sheet of glass itself, this assuring good contact with the sheet to be worked and permitting the automatic compensation of the wear of the tools in spite of the restrictive action of the stops.

In one preferred embodiment of the invention, the tools working on one face of the sheet are staggered in relation to those working on the other face, and the stops are disposed facing overhung parts of the staggered tools which bear on them by the intervention of the sheet of glass. The constancy of the working plane of the tools, both above and below, is thus positively assured.

A satisfactory result may also be obtained by providing the stops only on one side of the sheet of glass, providing that there is maintained on the tools which cooperate with these stops a pressure greater than, or at least equal to, the counter-pressure of the opposed tools, in order that they are not retracted to the spacing of the stops by the counter-pressure. In this modification, the tools situated at both sides of the sheet may be concentric if the tools cooperating with the stops are given a diameter greater than that of the tools opposite, and if the stops are disposed facing the overhung annular edge of the tools of larger diameter. The difference in diameter of the tools and possibly the dilference in working pressure of the latter may be compensated for by a difference in the speed of rotation of the tools in such manner as to equalise the work on the two faces of the sheet of glass.

In any case, the stops are advantageously constituted by bearing rollers which may be independent of the 2,746,213 Patented May 22, 1956 "ice normal supporting and driving rolls for the sheet of glass, or may be combined with the said rolls.

In the conventional manner, the tools situated at one side of the sheet of glass may be urged towards the latter simply by gravity, with a View to exerting on the glass the working pressure which is required and to compensating for the wear of the tools by an axial displacement within the range permitted by the stops. For the opposite tools, there is provided a mechanical or hydraulic device for compensating for wear, for example, suitable for maintaining them in contact with the sheet of glass under the desired pressure.

Embodiments of the invention are illustrated diagrammatically by way of example in the accompanying drawings, wherein:

Figure l is an elevation, and

Figure 2 is a plan view of a preferred arrangement;

Figure 3 is a plan view of an arrangement similar to that of Figures 1 and 2, suitable for the treatment of a larger sheet of glass;

Figures 4 and 5 are views of a modification, with partial sections taken respectively in a direction parallel to, and in a direction perpendicular to, the side members of the apparatus for grinding and/ or polishing glass;

Figures 6 and 7 are views corresponding to Figures 4 and- 5, respectively, but showing modifications;

Figures 8 and 9 are respectively an elevation and plan view of the application of the invention to tools mounted on a circle.

In all the figures, the sheet of glass which is to be worked simultaneously on both faces is indicated at 1, the rolls for supporting and driving the sheet are indicated at 2 and 2, the tools operating on the upper surface of the sheet at 3 and the tools operating on the lower surface at 4.

In the preferred arrangements (Figures 1 and 2 or 3), the upper tools 3 are staggered in relation to the bottom tools 4 and the supporting rolls 2, 2, positioned between the tools, are also staggered relatively to one another so as to be facing the overhung edges of the tools 3 and 4, for which they constitute stops stabilising the working plane of the tools 4 in the supporting plane of the sheet of glass on the rolls 2.

The arrangement according to Figure 3 is suitable for the treatment of relatively large sheets of glass where several tools are necessary for covering the area of the sheet 1; it is also suitable when a transverse balance is imparted to the side member of the apparatus.

Figures 4 and 5 show a modification in which the upper tools 3 are of a larger diameter than the lower tools 4, and these latter are framed by bearing rollers 5 situated in alignment with the supporting rolls of the sheetof glass and constituting stops which limit the downward movement of the upper tools 3.

In order that the upper tools 3 bear on the bearing rollers 5, the counter-pressure P of the lower tools must in this arrangement always remain less than or at the most equal to the pressure P exerted by the upper tools.

In Figures 4 and 5, the counter-pressure P is obtained by means of counterweights 6 fast with the cross member 7, with the interposition of racks 8 and 9 and toothed sectors 10. After being rendered operative by a progressive and simultaneous application of the tools to the sheet 1, the stop 11 releases the rising movement of the lower tool, the pressure P of which has been adjusted beforehand in such manner that P P. The difference between the two pressures P and P is absorbed by the rollers 5 to which the upper tool is applied.

The tools 4 applied against the lower surface of the sheet 1 will permanently maintain the contact with this latter by the action of the counterweight 6. In proportion with the wear thereof, the lower tools will be raised, their travel being constantly limited by the lower plane of the sheet. The raising of the tools in proportion to the wear is automatic.

Figures 6 and 7 comprise an arrangement in which the hydraulic pressure developed on the pistons 12 by means of the pump 13 is utilised for lifting the lower tools.

It will be understood that the operation will remain the same with the tools mounted on a circle or when they are mounted in any other grouping.

A suitable arrangement for the mounting on a circle is indicated diagrammatically in Figures 8 and 9, in which 4 represents lower tools mounted on a circle and 3 represents the upper tools, also mounted on a circle. In operation, the tools 3 turn by being suspended from the plates 14, their edges being supported by the rollers 5, while the lower tools 4 turn on the plates 15.

It is obvious that the invention is not limited to the embodiments and the details of construction which have been described and illustrated by way of example, and that the incorporation of modifications would not constitute a departure from the scope of the invention.

I claim:

1. Apparatus for simultaneously working both faces of a sheet of glass, comprising rotary tools arranged with their axes normal to the plane of the sheet at opposite sides of the latter and adjustable towards and away from the opposite faces of the glass sheet, the tools at the opposite sides of said glass sheet having portions overlapping in the direction along the glass sheet, the tools engaging one face of the sheet having parts thereof extending beyond the tools engaging the other face of the sheet in the direction along the latter, and work support and traversing means engaging said other face of the sheet at locations opposite said parts of the tools engaging said one face which extend beyond the tools engaging said other face, said work support and traversing means being rigidly mounted to oppose the forces exerted by said tools engaging said one face and, thereby, to maintain the sheet of glass in a constant plane.

2. Apparatus as in claim 1; wherein the sheet extends horizontally and the tools engaging the upper and lower faces of the sheet are of equal diameter with the axes of the tools engaging the upper face being offset longitudinally of the glass sheet with respect to the axes of the tools engaging the lower face of the glass sheet by a distance less than the radius of the tools so that the tools engaging the upper and lower surfaces overlap; and wherein said work support and traversing means includes rollers arranged transversely of the glass sheet and disposed against the upper and lower faces of the sheet at locations opposite the parts of the lower and upper tools, respectively, that extend beyond the related upper and lower tools.

3. Apparatus as in claim 1; wherein the tools engaging the opposite faces of the glass sheet have their axes in the same plane normal to the plane of the glass sheet and the tools engaging said one face of the glass sheet are of greater diameter than the tools engaging said other face, with said relatively large diameter tools exerting a pressure on the glass sheet greater than the pressure exerted on the latter by the tools of smaller diameter; and wherein said work support and traversing means includes supporting rolls engaging said other face of the glass sheet adjacent the smaller diameter tools at locations opposite the parts of the larger diameter tools extending beyond the peripheries of the related smaller diameter tools.

4. Apparatus as in claim 1; wherein said work support and traversing means includes supporting rollers which are rotatably driven to also perform the function of advancing the glass sheet past the tools.

5. Apparatus as in claim 1; wherein the diameter of the tools engaging said one face of the glass sheet is greater than the diameter of the tools engaging said other face, and the smaller diameter tools are rotated at a speed greater than the rotational speed of the larger diameter tools.

6. Apparatus for simultaneously working both faces of a horizontal glass sheet, comprising upper and lower tools rotatable about vertical axes above and below, respectively, the glass sheet and movable toward and away from the confronting faces of the sheet, said upper and lower tools being of the same diameter and having their axes offset in the direction along the glass sheet by a distance less than the radius of the tools so that the tools overlap with portions of the upper and lower tools extending beyond the lower and upper tools, respectively, in said direction along the glass sheet, upper traverse rollers engaging the upper surface of the glass sheet at locations opposite said portions of the lower tools extending beyond the upper tools, and lower traverse rollers engaging the lower surface of the glass sheet at locations opposite said portions of the upper tools extending beyond the lower tools, said upper and lower traverse rollers being rigidly mounted to resist the working pressures of the lower and upper tools, respectively, and thereby to maintain the glass sheet in a constant plane during the working of the latter.

7. Apparatus as in claim 6; wherein said traverse rollers are rotatably driven to also perform the function of advancing the glass sheet past the rotary tools.

References Cited in the file of this patent UNITED STATES PATENTS 1,716,861 Markland June 11, 1929 1,803,752 Ford May 5, 1931 1,863,854 Jeffery June 21, 1932 2,304,974 Waldron Dec. 15, 1942 2,313,493 Mols Mar. 9, 1943 2,567,163 Wallace Sept. 4, 1951 FOREIGN PATENTS 699,404 France Dec. 9, 1930 

